1. Field of the Invention
The present invention relates to an impact energy absorbing member that may be disposed between interior automotive trim pieces and body-in-white vehicle components or other structural components.
2. Background Art
Impact energy absorbing members are necessitated by motor vehicle safety standards relating to design of vehicles to minimize injury to occupants. In particular, head impact injuries may be reduced or minimized by including impact energy absorbing elements between interior trim pieces and structural members that define the vehicle body surrounding the passenger compartment. Examples of structural members in the passenger compartment of the vehicle include A, B and C pillars that support the vehicle roof and define window and door openings. Such impact energy absorbing members may also be inserted between a headliner and peripheral areas of a vehicle roof such as the windshield header and roof rails.
Different approaches have been taken to the design and arrangement of impact energy absorbing members. Impact energy absorbing members may be attached to the greenhouse support structure beams as is disclosed in U.S. Pat. No. 6,012,764 which discloses the concept of providing a deformable sheet that is secured to a greenhouse beam of an automobile. The deformable sheet has a plurality of frustoconical or spherical protrusions that extend toward the interior of the vehicle for absorbing impact energy.
Another approach disclosed in U.S. Pat. No. 5,680,886 is the provision of an impact energy absorber comprising of flexible pipe having a quadrangle shaped cross section that is arranged between inner and outer panels of an automobile body. The pipe sections are made of craft paper and aluminum foil that are spiral wrapped. The pipe sections are glued to the inner and outer panels of the automotive body. This design suffers from the disadvantage of being relatively costly to manufacture. A complex manufacturing process is required to form two layers of craft paper and a layer of aluminum into a strand that is wound to form a square shaped flexible pipe.
There is a need for a low cost, easy to manufacture impact energy absorbing member that is lightweight and provides excellent impact absorption as reflected in impact absorption tests normally conducted pursuant to Federal Motor Vehicle Safety Standards. There is also a need for an impact energy absorbing structure that is easily assembled to automotive headliners and interior trim pieces so that they are securely held in place and do not become dislodged during normal vehicle operation. A simple impact energy absorbing member that offers flexible design alternatives and exhibits uniform stiffness regardless of temperature is also needed.
According to the present invention, several embodiments of an impact energy absorbing member are disclosed that may be formed of sheet metal by a roll forming or sheet metal stamping operation. Alternatively, they could be formed as an extrusion or in an injection molding or blow molding process.
Another aspect of the invention also relates to the manner in which the impact energy absorbing member is secured to headliner or interior trim pieces. The impact energy absorber members are preferably oriented so that the walls of the impact energy absorbing member are not aligned so that they must be compressed when impacted in the direction of the expected impact force. The walls of the impact energy absorbing member preferably extend in an oblique or acute angle relative to the expected angle of impact force. As a result, the impact energy absorbing member is deformed in such a way that the deformation is focused at the corners of the impact absorbing member where adjacent walls intersect. At least some of the corners are caused to deform so that the walls joined at the corner are caused to converge forming a corner having a more acute angle of intersection.
Another aspect of the invention relates to the method in which the impact energy absorbing members are secured to headliners and vehicle trim members. The impact absorbing members may have a wall including holes that are pressed against a hot melt glue or other adhesive that is applied either to the wall of the impact absorbing member or the interior trim piece or headliner such that the adhesive flows into the holes and forms a head on the interior of the wall. The adhesive extruded through the hole forms a head on the inside of the impact absorbing member and functions in a manner similar to a rivet connection. A pressure sensitive adhesive in liquid paste or tape form could also be used to attach the members. Alternatively, stamped rosettes may be formed in a wall that are pressed into engagement with the headliner or trim piece.
These and other aspects of the invention will be more fully understood in view of the attached drawings and following detailed description of various embodiments of applicant""s invention.